Programming language: Programming language: FORTRAN77 full language as specified in the ANSI standard: X3.9-1978: American National Standard Programming Language FORTRAN. American National Standards Institute, New York 1978. Extension: INCLUDE statement of FORTRAN90. Character set: Code: Character set of FORTRAN77 with capital letters (49 characters including the space): ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 =+-*/(),.$': Comments and character strings: ASCII characters of the 7-bit table. Line length: 72 characters Preferred code layout: Indentation: Documentation and extensive comments at the beginnings of subroutines: columns 3, 7, 15, 17, 19, etc. with step 2. FORTRAN statements and comments within statements: columns 7, 9, 11, etc. with step 2. Insides of DO loops and IF statements are indented. Indentation of the continuation lines is haphazard in this version. Example forms of the FORTRAN statements and of the spacing: A=B+5.*(E+F) no spaces in assignment statements and expressions, except when matching similar expressions in succeeding lines. GO TO 12 GO TO (10,20,30)K IF(I.EQ.J) GO TO 30 IF(A.GT.B) THEN ELSE IF(C.GT.D) THEN END IF DO 20 I=1,15 BLOCK DATA BACKSPACE CALL VEL(N,COOR,F) SUBROUTINE VEL(N,COOR,F) PARAMETER (PI=3.14159) COMMON/ABC/IR,FF,HH COMMON IR,FF,HH DATA R/4.,2.,1./,K/0/ READ(LUN,*) L,M,(BER(I),I=LS,MS),ALFA,BETA but: READ (LUN,*) L,M,(BER(I),I=LS,MS),ALFA,BETA WRITE(LUN,*) L,M,(BER(I),I=LS,MS),ALFA,BETA Miscellaneous: All sentences in documentation should be ended by a dot. Individual sections of the code may be separated by blank lines with C in the first column. Only CONTINUE and FORMAT statements should be labeled. Specific names of the intrinsic functions are preferred to generic ones. Error messages: The error messages are most frequently written by statements like CALL ERROR('314 in SUBR: Brief description') or CALL ERROR('PROG-04: Brief description') They are spread over all files and are described inside individual routines. SUBROUTINE ERROR etc.
Control of screen output: Output to the * external unit is intended for the screen. It is assumed that the first character of each output line is a control character: ' ' to advance to the next line, and '+' to rewrite the last line. If the compiler and operating system does not support this convention, it is adviced to pipe the screen output with user-defined filter in order to achieve the best look of the output screen. The width of the screen is usually assumed to be at least 79 characters.